Maggie Brennan half walked, half ran along Deptford Church Street. She was talking on the phone and reading a file and looking for the address in the A–Z. It was the second day of the week, and she was already two days behind schedule. This didn’t include the caseload she had inherited from a colleague who was now on permanent sick leave.

“No,” said Maggie, into the phone. She looked at her watch. “I’ll try to get to the meeting before you finish.”

She put the mobile into her pocket. She was thinking of the case she’d just come from. A three-year-old with bruises. Suspicious bruises, the doc tor in A&E had said. Maggie had talked to the mother, looked at the child, checked out the flat where they lived. It was horrible, damp, cold, but not obviously dangerous. The mother said she didn’t have a boyfriend, and Maggie had checked the bathroom and there was no razor. She had insisted that the child had fallen down the stairs. That’s what people said when they hit their children, but even so, three-year-olds really did fall downstairs. She’d only spent ten minutes there, but ten hours wouldn’t have made much difference. If she removed the child, the prosecution would probably fail and she would be disciplined. If she didn’t remove the child and he was found dead, there would be an inquiry; she would be fired and maybe prosecuted. So she’d signed off on it. No immediate cause for concern. Probably nothing much would happen.

She looked more closely at the A–Z. Her hands were cold because she’d forgotten her gloves; her feet were wet in their cheap boots. She’d been to this hostel before, but she could never remember where it was.

Howard Street was a little dead end, tucked away somewhere toward the river. She had to put her reading glasses on and move her finger around on the map before she found it. Yes, that was it, just a couple of minutes away. She turned off the main street and found herself unexpectedly next to a churchyard.

She leaned on the wall and looked at the file on the woman she was going to see. There wasn’t much at all. Michelle Doyce. Born 1959. A hospital discharge paper, copied to the Social Services department. A placement form, a request for an evaluation. Maggie flicked through the forms: no next of kin. It wasn’t even clear why she had been in the hospital, although from the name of it, she could see that it was something psychological. She could guess the results of the evaluation in advance: just sheer general hopelessness, a pathetic middle-aged woman who needed somewhere to stay and someone to drop in just to keep her from wandering the streets. Maggie looked at her watch. There wasn’t time for a full evaluation today. She could manage a basic checkup to make sure that Michelle was not in imminent danger, that she was feeding herself—the standard checklist.

She closed the file and walked away from the church along a housing estate. Some of the flats were sealed up, with metal sheets bolted on to the doors and windows, but most were occupied. From the second level, a teenage boy emerged from a doorway and walked along the balcony, his hands stuffed into the pockets of his bulky jacket. Maggie looked around. It was probably all right. It was a Tuesday morning, and the dangerous people were mostly still in bed. She turned the corner and checked the address she’d written in her notebook. Room One, 3 Howard Street. Yes, she remembered it now. It was a strange house that looked as if it had been built out of the same materials as the housing estate and then had decayed at the same rate. This hostel wasn’t a proper hostel at all. It was a house rented cheaply from a private landlord. People could be put there while the services made up their minds about what to do with them. Usually they just moved on or were forgotten about. There were some places Maggie visited only with a chaperone, but she hadn’t heard anything particular about this one. These people were mainly a danger to themselves.

She looked up at the house. On the second floor a broken window was blocked up with brown cardboard. There was a tiny paved front garden and an alley that went along the left side of the house. Beside the front door a bin bag had burst, but it had only added to the rubbish that was strewn everywhere. Maggie wrote a one-word note. There were five buzzers next to the front door. They didn’t have labels next to them, but she pressed the bottom one, then pressed it again. She couldn’t tell whether it was working. She was wondering whether to knock on the door with her fist or look through the window when she heard a voice. Looking round, she saw a man right behind her. He was gaunt with wiry ginger hair tied back in a ponytail and piercings right across his face. She stepped to one side when she saw the man’s dog, a small breed that was technically illegal, though it was the third she’d seen since she’d left Deptford station.

“No, he’s a good one,” the man said. “Aren’t you, Buzz?”

“Do you live here?” Maggie said.

The man looked suspicious. One of his cheeks was quivering. Maggie took a laminated card from her pocket and showed it to him. “I’m from Social Services,” she said. “I’m here to see Michelle Doyce.”

“Go on, Buzz,” he said. Maggie heard the clatter of the dog’s paws inside and up the stairs, and the man disappeared after him.

As soon as she stepped inside, Maggie was hit by an odor of damp and rubbish and fried food and dog shit and other smells she couldn’t place. It almost made her eyes water. She closed the front door behind her. This must once have been the hallway of a family house. Now it was piled with pallets, tins of paint, a couple of gaping plastic bags, an old bike with no tires. The stairs were directly ahead. To the left, what would have been a door to the front room was blocked up. She walked past the side of the stairs to a door further along. She rapped on it hard and listened. She heard something inside, then nothing. She knocked again, several times, and waited. There was a rattling sound, and then the door opened inwards. Maggie held out her laminated card once more.

“Michelle Doyce?” she said.

“Yes,” said the woman.

It was difficult for Maggie to define even to herself exactly what was strange about her. She was clean and her hair was brushed, but perhaps almost too brushed, like that of a small child who had wetted her hair and then combed it so that it lay flat over her head, thin enough to show the pale scalp beneath. Her face was smooth and pink, with a dusting of fuzzy hair. Her bright red lipstick extended just a little too far off her lips. She wore a baggy, faded, flowery dress. Maggie identified herself and held out the card.

“I just wanted to check up on you, Michelle,” she said. “See how you are. Are you all right? All right in yourself?”

The woman nodded.

“Can I come in?” said Maggie. “Can I check everything’s OK?”

She stepped inside and took out her notebook. As far as she could tell from a glance, Michelle seemed to be keeping herself clean. She looked as if she was eating. She was responsive. Still, something felt odd. She peered around in the shabby little anteroom of the flat. The contrast with the hallway of the house was impressive. Shoes were arranged in a row, a coat hung from a hook. There was a bucket with a mop leaning against the wall in the corner.

“How long have you been here, Michelle?”

The woman frowned. “Here?” she said. “A few days.”

The discharge form had said the fifth of January and today was the first day of February. Still, that sort of vagueness wasn’t really surprising. As the two women stood there, Maggie became aware of a sound she couldn’t quite place. It might be the hum of traffic, or a vacuum cleaner on the floor above, or a plane. It depended on how far away it was. There was a smell also, like food that had been left out too long. She looked up: the electricity was working. She should check whether Michelle had a fridge. But, by the look of her, she’d be all right for the time being.

“Can I have a look round, Michelle?” she said. “Make sure everything’s OK?”

“You want to meet him?” said Michelle.

Maggie was puzzled. There hadn’t been anything on the form. “Have you got a friend?” she said. “I’d be happy to meet him.”

Michelle stepped forward and opened the door to what would have been the house’s main back room, away from the street. Maggie followed her and immediately felt something on her face. At first, she thought it was dust. She thought of an Underground train coming, blowing the warm grit into her face. At the same time, the sound got louder, and she realized it wasn’t dust but flies, a thick cloud of flies blowing against her face.

For a few moments she was confused by the man sitting on the sofa. Her perceptions had slowed and become skewed, as if she were deep underwater or in a dream. Crazily, she wondered if he were wearing some sort of diving suit, a blue, marbled, slightly ruptured and torn diving suit, and she wondered why his eyes were yellow and cloudy. And then she started to fumble for her phone and she dropped it, and suddenly she couldn’t make her fingers work, couldn’t get them to pick the phone up from the grimy carpet, as she saw that it wasn’t any kind of suit but his naked, swollen, rupturing flesh, and that he was dead. Long dead.